Easiest way to live plot?

Using “plot!” I get something like this:

It is constantly adding new legend entries, which I do not want, and it is not continuing the previous lines, ie. I expected a straight line but it is constantly starting from one again. Any suggestions?

The code:

function test()
    i = 1
    while true
        if i == 1
            difFiles = _dirFiles()
            i = 0
        else
            curFiles = _dirFiles()
            sleep(2.5)
            newFiles = _dirFiles()
            difFiles = setdiff(newFiles,curFiles)
        end
        data     = readBi4Body(MovingSquare,Points,difFiles)
        y        = getindex.(mean.(data),1)[:]
        pp = plot!(y)
        display(pp)
    end
end

Kind regards